

THE BRITISH FERNS. 
$ v.—LoMARIEE or BLECHNEA.—Sori linear, transverse to the veins, i. e. 
ranged longitudinally between the midrib and margins, covered by 
special linear indusia. 
10. Blechnum.—Sori forming a continuous line on each side of, 
and parallel with the midrib, and within the margin. 
$ vi. —PIERIDEA.—Sori linear, continuous, transverse to the veins, covered by 
the reflexed margin of the frond, which is altered in texture, 
becoming indusiate. 
11. Pteris.—Sori forming a continuous marginal line, covered by 
the indusium-like reflexed edge of the segments of the 
frond. 
$ vii.—ADIANTEX.—Sori oblong, rarely elongated, borne on the veins of the under 
surface of the transverse indusia, and laterally confluent ; indusium 
formed of the reflexed margin of the frond, altered in texture. 
12. Adiantum.—Sori transverse, growing on the reflexed indu- 
sium-like apices of the lobes; hence resupinate. 
$ viii. — CYSTOPTERIDEZ. — Sori punctiform, covered while young by cucullate 
indusia, affixed posteriorly, and inflected hood-like over them. 
18. Cystopteris.—Sori covered by ovate cucullate or hooded 
indusia, which are attached by their broad base. 
§ ix.—PERANEMEX or WoopsrEZX.—Sori punctiform, involucrate, i.e. with 
the scale-like membrane fixed beneath the sorus. 
14. Woodsia.—Sori within involucres whose margin is divided 
into incurved capillary segments. 
TRIBE IL.— Trichomaninese. — Fructifications extrorse-marginal ; spore- 
cases without valves bursting irregularly, clustered on veins (recep- 
tacles) which project from the frond, and are surrounded by urn- 
shaped or two-valved involucres ; ring horizontal or oblique, complete. 
15. Trichomanes.—Receptacles exserted, sporangiferous at the 
base, where they are surrounded by urn-shaped involucres 
of the same texture as the frond. 

